Process of producing sulphonic acids and sulphonates



Patented Apr. 24, 1934 UNITED STATES PATENT OFFICE PROCESS OF PRODUCING SULPHONIC ACIDS AND SULPHONATES poration of Delaware No Drawing. Application February 17, 1928,

Serial No. 255,179

14 Claims.

This invention relates to the treatment of petroleum oils for the manufacture and production of valuable by-products. The invention relates more particularly to the manufacture of sulphonic acids, particularly sulphonic acids of the water soluble type and to the manufacture of water soluble sulphonates therefrom.

One of the objects of this invention is to provide a process whereby hydrocarbons may be efiectively treated for the production of sulphonic acids. Another object is to disclose a process whereby large yields of desirable sulphonic acids are obtained without producing appreciable quantities of undesirable sulphonic acids and other compounds.

Another object is to disclose a process whereby concentrated solutions of sulphonic acids may be obtained. Another object is to provide a method whereby relatively inert and non-amenable hydrocarbons and products are removed from the operation before the substantially complete conversion of amenable products to sulphonic acids takes place.

Another objectis to disclose a specially prepared hydrocarbon stock which is highly amenable to treatment for the production of sulphonic acids. Another object is to disclose a process whereby water soluble sulphonates are produced in a highly concentrated form.

sulphonic acids have been made heretofore but prior processes relating to this subject involved a large number of steps or treatments and resulted in mixtures of sulphonic acids and the yield obtained was relatively small. It has been the practice, for example, to treat an oil stock with successive batches of sulphonating agent such as, for example, sulphuric acid, thereby producing sludges, containing both water soluble and oil soluble sulphonic acids, the latter being removed by extraction with a suitable solvent or by selectively discarding the particular sludge characterized by the presence of the oil soluble sulphonic acids.

Various oil stocks have been used in the manufacture of sulphonic acids, the yield of such sulphonic acids depending somewhat upon the character of the oil stock being used. Furthermore, the yield is dependent to a certain extent upon the proportion of sulphonatable constituents present in the oil stock. Generalhr, from to about 40% of the charging stock or petroleum is composed of constituents amenable to sulphonation and the development of sulphonic acids therefrom. In other words, the treatment of'oils only partly amenable to sulphonation results in the presence of unsulphonatable oil during the process and requires the use of relatively large quantities of sulphuric acid, the handling of large volumes of oil and the production of a relatively small yield. Losses by occlusion, entrainment and absorption are relatively high.

In the present method the formation of oil soluble sulphonic acids is largely avoided and such minor quantities of these acids as will be produced are easily removed by mechanical separation during the later steps of the process. Large yields of water soluble sulphonic acids are obtained and the process is carried out substantially free from the presence of unsulphonatable oil or products. The yields are extremely high and the concentration of the sulphonic acids produced is much higher than that resulting from the operation of other processes. Instead of carrying out the process on an oil containing only, say, 20 or 30% of sulphonatable constituents, our process is directed toward the production and utilization of an oil which is substantially 100% amenable to sulphonation.

Briefly, the process consists of the following steps: Any suitable petroleum oil is first treated with sulphur dioxide, preferably in the liquid state so as to dissolve unsaturated hydrocarbons in the liquid sulphur dioxide. Stratification of the oil 5 takes place, the lower portion consisting mainly of sulphur dioxide containing unsaturated and other constituents amenable to sulphonation. The upper layer consists of a highly refined petroleum oil. Separation of the lower layer from the oil is accomplished, sulphur dioxide removed from such lower layer and the remaining oil then emulsified with a substantially equal volume of concentrated sulphuric acid in one application. This treatment results in the production of large quantities of water soluble sulphonic acids and although it is not known exactly how the evolution of oil soluble sulphonic acids is prevented, and it is thought that the method of applying the sulphuric acid has an important bearing upon this reaction. This process will now be more completely described.

In carrying out the process, it is desirable to first dry the oil so that there is no moisture present, in as much as the presence of moisture during treatment with liquid sulphur dioxide tends to cause the formation of corrosive acids. Various methods of treating petroleum oils with liquid or gaseous sulphur dioxide have been disclosed heretofore for the purpose of refining the petroleum oils, particularly, in an effort to produce highly refined, lubricating oil stock. The details of this step, therefore, will not be reviewed as they are well known in the art. In all events, an extraction is made of a petroleum oil with sulphur dioxide and the sulphur dioxide removed from the extracted constituents in any desirable manner as, for example, by vaporization from said constituents. It is desirable, however, that this extract be free from sulphur dioxide and that substantially no moisture be present therein, as we have found that the presence of water reduces the effectiveness of later treatment and entails the use of larger quantities of acid.

It will be found that the extract obtained by treatment of petroleum oil with liquid sulphur dioxide is substantially 100% amenable to the following process and produces extremely large yields of water soluble sulphonic acids. These extracted constituents are then treated with strong sulphuric acids in the proper amount and strength to insure complete reaction and sul-.

phonation of all amenable constituents without the generation of excessive heat. These constituents should be treated with sulphuric acid of preferably over 90% strength and fuming sulphuric acid of about 103% equivalent has been successfully used. The full amount of acid required (as preferably determined by a prior test) may be placed in a suitable vessel such as a leadlined agitator or other mixing device and the oil slowly added thereto with violent agitation during the admixture, using compressed air, mechanical actuated paddles, or other stirring means to secure a thorough and intimate mixture in the form of an emulsion. The rate at which the oil may be introduced is such that emulsification of the oil and acid is immediate and continuous, and at no time during the mixing operation should there be any appreciable amount of unemulsified oil present in the mass. The evolution of heat during this step is a further controlling factor and the mixture of oil and acid should not be accomplished in such a way, or at such rate, as to cause excessive heating, the temperature of the mixture being preferably kept at about 130 F., or at least below 150 F. Temperatures materially above this tend to cause the formation of oil soluble reaction products and thereby reduce the yield of desirable water soluble sulphonic acids.

While the oil may be added to the entire acid body as described, satisfactory results may be proportions paratus may be used provided the oil, sulphonating agent, temperatures, and volumes of reagents are controlled substantially as described.

To the emulsion of oil, acid and products of reaction, fresh water may then be added in a volume approximately equal to the volume of the original acid used and the mixture may again be blown or otherwise agitated to secure a thorough dispersal of water therethrough. This ad dition of water is made to cause stratification of the emulsion and suflicient water should be added to produce a dilute sulphuric acid of about to 60% strength as acid of this concentration insures proper "salting ou of the water soluble sulphonic acids.

Insuflicient dilution, that is, the presence of acid in higher concentrations interferes with stratification and results in an incomplete breakdown of the emulsion, while appreciably weaker solutions of acid tend to dissolve the sulphonic acids and thereby reduce the yield. Considerable heat may be generated at this stage by the mixing of unconibined sulphuric acid and water and no attempt is necessary in an efiort to dissipate such heat. On the contrary, the mixing vessel may be insulated against heat losses in order to take advantage of the effect of heat in improving the efiiciency of the later separation of the components of the mixture. An increase of temperature above about 130 F., or 150 F., at this stage of the process apparently does not reduce the yield.

After the water is thoroughly, incorporated into the mixture, the mass is then allowed to stand and stratification takes place readily, the emulsion breaking down and separating into two or three layers, the lower layer comprising sulphuric acids in relatively dilute solution, the middle layer being a sludge consisting almost entirely of water soluble sulphonic acids and the upper layerbeing a small quantity of highly acid treated lubricating oil which may be used for any desired further processing.

This third acid treated oil layer may be absent, depending upon the character of the oil extracted originally with liquid sulphur dioxide and the conditions present during such extraction. While the sulphonic acid sludge is freely soluble in hot water, it is not soluble in dilute sulphuric acid so that practically the entire water content of the mixture goes into the lower layer, leaving the sludge layer substantially undiluted.

After removing the lower layer of dilute sulphuric acid. the middle layer comprising water soluble sulphonic acids may be drawn off into storage or treated at once for the production of metal sulphonates which is one of the objects of this invention. If a third upper layer of acid treated oil was formed during stratification, it may be separately removed at this point or the water soluble sulphonic acids together with the relatively small oil layer may be treated together. The third or upper layer of acid treated oil, when present, contains the oil soluble constituents produced during the process so that a clear separation between water soluble sulphonic acids and oil soluble constituents may be accomplished by separating the middle layer from the upper or third layer.

In case both the dilute acid layer and the upper oil layer have been removed, hot water in an amount approximately equal to the original sulphuric acid used may then be added to the middle layer containing sulphonic acids and the resulting solution neutralized with metallic oxides or hydrates or similar substances capable of forming water soluble compounds with such sulphonic acids. It has been found that the solubility of the sulphonic acids increases greatly with temperature and for this reason hot water is used. temperatures in excess of about 160 F., having proven very satisfactory. The product resulting from this process consists of water soluble sulphonates in aqueous solution and may be concentrated to any desired degree for use as an emulsifier, spreader, detergent and other purposes. This concentration may be effected in a suitable evaporator or it may be avoided entirely as a separate step by changing the amount of water added in the neutralization step, thus controlling the proportion of water or the concentration of the final product. For neutralization, any oxide or hydroxide of a metal capable of forming water soluble compounds with the sulphonic acids may be used. For example, oxides or hydroxides of sodium, potassium, lithium, rubidium and even ammonium are suitable. It

is desirable to use an excess of alkali during neutralization and formation of water'soluble sulphonates so as to prevent occlusion of oil soluble constituents. Preferably the resulting aqueous solution of water soluble sulphonates should have a hydrogen ion concentration of about 10- to 10 gram atoms'of hydrogen ion per liter.

While the neutralization step has been d scribed as following the removal of the upper or oil layer, the operation may be satisfactorily performed after the removal of only the dilute uncombined sulphuric acid. The oil layer may be later removed from the neutralized sulphonates either after the addition of hot water or after the addition of both hot water and metallic oxides or hydrates, in which case the use of hot water in the first part of the neutralizing step has the further function of assisting in the separation of the oil present.

Although particular products and method of procedure have been described in detail, it is to be understood that the process is not limited to its application to particular hydrocarbon or petroleum oil distillates, nor to the strength or quantity of sulphuric acid used nor to kind or character of neutralizing agent, the invention being of the scope of the. following claims and embracing all modifications and changes covered thereby.

We claim:

1. A process of treating petroleum oils to produce sulphonic acids comprising, extracting a petroleum oil with liquid sulphur dioxide, removing sulphur dioxide from the extracted constituents, forming an emulsion by bringing said extracted constituents containing sulphonatable products, during agitation, into intimate contact with sulphuric acid in quantity and strength adapted to sulphonate substantially all constituents amenable to sulphonation, adding water to the emulsion to cause stratification thereof, removing dilute sulphuric acid from the stratified mixture, and separately removing water soluble sulphonic acids from the mixture.

2. A process of treating petroleum oils to produce sulphonic acids comprising, extracting a petroleum oil with liquid sulphur dioxide, removing sulphur dioxide from the extracted constituents, bringing said extracted constituents containing sulphonatable products into intimate contact in one application with sulphuric acid in quantity and strength adapted to sulphonate substantially all products amenable to sulphonation, agitating the mixture to form an emulsion, maintaining the temperature of the emulsion at a temperature below 150 F., adding water to the emulsion to cause stratification, and removing dilute sulphuric acid and separately removing water soluble sulphonic acids from the stratified mixture.

3. A process of treating petroleum oils to produce sulphonic acids comprising, extracting sulphonatable products from a petroleum oil having the characteristics of lubricating oil distillate with liquid sulphur dioxide in the substantial absence of moisture, separating said products from the sulphur dioxide, bringing said extracted prodiicts into intimate contact in one application with concentrated sulphuric acid in quantity adapted to sulphonate substantially all products amenable to sulphonation, agitating the extracted products and acid during said contacting to form an emuL sion, dispersing water throughout the emulsion to cause stratification thereof, removing dilute sulphuric acid from the stratified mixture, and separately collecting water soluble sulphonic acids from the residue. of said stratified mixture.

4. In a process of treating petroleum oils to produce sulphonic acids, the steps of adding a sulphur dioxide extract of petroleum oil containing sulphonatable constituents, during agitation, to a body of sulphuric acid in quantity and strength suflicient to sulphonate all constituents amenable to sulphonation, forming a stable emulsion by such agitation and addition and maintaining the temperature of the emulsion at below 150 F.

5. A process of treating petroleum oils to produce water soluble sulphonic acids comprising adding a sulphur dioxide extract of petroleum oil containing sulphonatable constituents, during agitation, to a body of sulphuric acid in quantity and strength sufficient to sulphonate all constituents amenable \to sulphonation, forming an emulsion by such agitation and addition, dispersing water throughout the emulsion in sufficient quantity to cause stratification thereof but not sufiicient to form a dilute sulphuric acid solution in which sulphonic acids are soluble, and removing dilute sulphuric acid and separately removing water soluble sulphonic acids from the stratified mixture.

6. A process of treating petroleum oils to produce water soluble sulphonates comprising, extracting sulphonatable products from petroleum oil with liquid sulphur dioxide, separating said products from the sulphur dioxide, bringing said extracted products into intimate contact with sulphuric acid in quantity and strength adapted to sulphonate substantially all products amenable to sulphonation, adding water to the emulsion thus formed to cause stratification thereof, removing dilute sulphuric acid from the stratified mixture, and neutralizing the residual mixture containing water soluble sulphonic acids with an alkali to form water soluble sulphonates.

'7. A process of treating petroleum oil to produce water soluble sulphonates comprising, extracting sulphonatable products from petroleum oil with liquid sulphur dioxide, separating said products from the sulphur dioxide, bringing said extracted products into intimate contact with sulphuric acid in quantity and strength adapted to sulphonate substantially all products amenable to sulphonation, adding water to the emulsion thus formed to cause stratification thereof, removing dilute sulphuric acid from the stratified mixture, neutralizing the residual mixture containing water soluble sulphonic acids with an alkali to form water soluble sulphonates, and separating unsulphonated oil and oil soluble sulphonates from the neutralized mixture.

8. A process of treating petroleum oils to produce water soluble sulphonic acids comprising adding a sulphur dioxide extract of petroleum oil containing sulphonatable constituents, during agitation, to a body of sulphuric acid in quantity and strength suflicient to sulphonate all constituents amenable to sulphonation, forming an emulsion by such agitation and addition, dispersing water throughout the emulsion in sufficient quantity to cause stratification thereof but not sufficient to form a dilute sulphuric acid solution in which sulphonic acids are soluble,

separately removing dilute sulphuric acid and Water soluble sulphonic acids from the stratified mixture, and neutralizing said water soluble sul-= phonic acids with an excess of alkali to form an aqueous solution of sulphonates.

9. A process of treating petroleum oils to produce Water soluble sulphonates comprising adding a sulphur dioxide extract of petroleum oil containing sulphonatable constituents, during agitation, to a body of sulphuric acid in quantity and strength sufiicient to sulphonate all con stituents amenable to sulphonation, forming an emulsion by such agitation and addition, dispersing water throughout the emulsion in sufficient quantity to cause stratification thereof, but not sufiicient to form a dilute sulphuric acid solution in which sulphonic acids are soluble, separately removing dilute sulphuric acids and water soluble sulphonic acids from the stratified mixture, neutralizing said water soluble sulphonic acids with an excess of alkali to form an aqueous solution of sulphonates, and to stratify unsulphonated oil containing oil soluble sulphonates, and separating said unsulphonated oil with oil soluble sulphonates from the neutralized solution.

10. A process of treating petroleum oils to produce sulphonates comprising, extracting a petroleum oil with liquid sulphur dioxide, removing sulphur dioxide from. the extracted constituents, bringing said extracted constituents containing sulphonatable products into intimate contact with sulphuric acid in quantity and strength adapted to sulphonate substantially all products amenable to sulphonation, agitating the mixture to form an emulsion, maintaining the temperature at about below 150 F., dispersing water throughout the emulsion to cause Stratification thereof, separately removing dilute sulphuric acid and water soluble sulphonic acids from the strati fied mixture and neutralizing sulphonic acids in the water solution with a metallic oxide or hydrate capable of forming water soluble sulphonates.

11. A process of treating petroleum oils to produce water soluble sulphonic compounds comprising, extracting sulphonatable products from petroleum oil with liquid sulphur dioxide in the substantial absence of moisture, separating said products from the sulphur dioxide, bringing said extracted products into intimate contact with concentrated sulphuric acid in quantity adapted to sulphonate substantially all constituents amenable to sulphonation in one application, agitating the mixture to form an emulsion, maintaining the temperature during the mixing at below about 150 F., mixing the emulsion with water in an amount capable of forming a dilute acid of about 50% to 60% concentration, separately removing dilute sulphuric acid from the stratified mixture, adding hot water to the residual mixture in an amount depending upon the desired concentration of product, and neutralizing sulphonic compounds present in the diluted mixture with sulficient alkali to make the hydrogen ion concentration of the aqueous component of the residual mixture from 10- to 10-. gram atoms of hydrogen ion per liter.

12. A process of treating petroleum oils to produce sulphonic acids comprising, adding products extracted by sulphur dioxide from petroleum oil to sulphuric acid in quantity and strength adapted to sulphonate substantially all constituents amenable to sulphonation in one application, agitating the oil and acid during admixture to form an emulsion, adding to the emulsion with agitation an amount of water capable of forming a dilute sulphuric acid of about 50% to 60% concentration and to cause Stratification of the emulsion, and separately removing dilute sulphuric acid and water soluble sulphonic acids from the stratified mixture.

13. A mixture of water soluble sulphonates obtained from an emulsion of constituents extracted from petroleum oil by liquid sulphur dioxide and sulphuric acid in strength and quantity sufficient to sulphonate substantially the entirecontent of sulphonatable constituents present in said extract, said mixture of water soluble sulphonates being in aqueous solution of hydrogen ion concentration of from 10- to 10- gram atoms of hydrogen ion per liter.

14. In a process of producing sulphonic acids from petroleum oils, the steps of removing sulphur dioxides from unsaturated compounds and sulphonatableconstituents extracted from petroleum oil with liquid sulphur dioxide, bringing said SOa-free unsaturated and sulphonatable constituents into intimate contact in one application with concentrated sulphuric acid in quantity adapted to sulphonate substantially all products amenable to sulphonation, agitating the extracted constituents and acid during said contacting to form a stable emulsion, then breaking said emulsion by dispersing water therethrough, permitting the broken emulsion to stratify, removing dilute sulphuric acid from the stratified mixture, and separately removing a sludge containing water soluble sulphonic acids from the stratified mixture for subsequent separation of sulphonic acids therefrom.

ROBERT T. OSBORN. RODERICK CRAIG. 

